6 replies to this topic

[paul_s]

I noticed when I turned the engine off before the lights this morning, that the headlight levelling motors were making a whirring noise. I flipped the levelling switch and the whirring changed pitch, but it didn't go away.

It stops when I turn the lights off, then starts up again as soon as I turn them back on again.

Any suggestions?

[minisilverbullet]

Not on a mini, but i had this on an alfa 147, turned out the gear on the motor wasn't engaged.

Not so helpful: but have you ever used them?

Edited by minisilverbullet, 23 October 2012 - 10:47 AM.

[paul_s]

Hmm, sounds like it could be it - I'll have to wait 'til I get home and take them apart. Bit of a pain as I need to use the car for work so I hope I can sort it in the dark!

I've never used them to be honest, I did move the switch the other day though, just to see if made a noticeable difference. It didn't, but I might know why now

[paul_s]

I took the driver's side motor off and it's not moving in/out so that's that sorted, new motors it is I guess!

[Deeppockets]

Picking up on this old thread, I have had similar problems but thought I would investigate before spending on a new unit at the current market rate of £60 (XBS100140).

 

The units are bonded together so 'not serviceable' but was opened by tapping a wood chisel into the seam. Once a click was heard that part of joint had been cracked, moving around the seam until the whole length was cracked and the back of the unit be removed. There is a lip as part of the seam which can easily be knocked off by the chisel so careful not to be too heavy handed.

 

With the back off the unit off the circuit/mid board can be lifted away revealing the electric motor and plastic gears.  On the circuit board protruding into the gear space is the position sensing potentiometer (pot) - if the gears had not failed and moved without difficulty (including the pin) then it was likely the culprit was this pot.

 

I discovered the pot is not soldered but plugged into board pin sockets and can be pulled out. The pot consists of a resistive track surface mounted onto a ceramic base (~2.2k ohms) with a second conductive track for the wiper. Both ends of the resistive track are back to two of the three pins, centre and right from the track/wiper side (pins at bottom). The wiper moved up/down the resistive track and likely to provide a position reference voltage with a regulated voltage applied across the resistor.

 

The pot's ceramic base was removed from the plastic carrier easily by easing the small catches. This was cleaned with a cotton bud & alcohol, as were the wiper brushes before replacing.

 

After cleaning the pot pins and sockets with alcohol I reassembled applying white PTFE grease to the main pin, checking the pot readings from the back of the circuit board, gluing & sealing (HV super glue & Hylomar in the gaps) and a couple of cable ties around the body for reassurance. Tested on car – both now working in unison.

 

The only tricky part is opening the case, but even this was not as hard as I had expected – took about 10mins.  There is useful YouTube video on the Land Rover Disco 2 units which have different pin adjustment and connector arrangement otherwise same internals:

Likely these AMR2706 units could be scavenged for parts if necessary.

Edited by Deeppockets, 15 November 2020 - 12:57 PM.

[FlyingScot]

Picking up on this old thread, I have had similar problems but thought I would investigate before spending on a new unit at the current market rate of £60 (XBS100140).

 

The units are bonded together so 'not serviceable' but was opened by tapping a wood chisel into the seam. Once a click was heard that part of joint had been cracked, moving around the seam until the whole length was cracked and the back of the unit be removed. There is a lip as part of the seam which can easily be knocked off by the chisel so careful not to be too heavy handed.

 

With the back off the unit off the circuit/mid board can be lifted away revealing the electric motor and plastic gears.  On the circuit board protruding into the gear space is the position sensing potentiometer (pot) - if the gears had not failed and moved without difficulty (including the pin) then it was likely the culprit was this pot.

 

I discovered the pot is not soldered but plugged into board pin sockets and can be pulled out. The pot consists of a resistive track surface mounted onto a ceramic base (~2.2k ohms) with a second conductive track for the wiper. Both ends of the resistive track are back to two of the three pins, centre and right from the track/wiper side (pins at bottom). The wiper moved up/down the resistive track and likely to provide a position reference voltage with a regulated voltage applied across the resistor.

 

The pot's ceramic base was removed from the plastic carrier easily by easing the small catches. This was cleaned with a cotton bud & alcohol, as were the wiper brushes before replacing.

 

After cleaning the pot pins and sockets with alcohol I reassembled applying white PTFE grease to the main pin, checking the pot readings from the back of the circuit board, gluing & sealing (HV super glue & Hylomar in the gaps) and a couple of cable ties around the body for reassurance. Tested on car – both now working in unison.

 

The only tricky part is opening the case, but even this was not as hard as I had expected – took about 10mins.  There is useful YouTube video on the Land Rover Disco 2 units which have different pin adjustment and connector arrangement otherwise same internals - . Likely these AMR2706 units could be scavenged for parts if necessary.

 

Excellent - thanks for sharing!

 

PINNED as this will be an issue going forwards.

 

FS

Edited by FlyingScot, 13 November 2020 - 07:45 PM.

[Deeppockets]

Glad it may be of use. A couple of more thoughts came to me regarding these headlamp levelling units:

• The position sensing pot is exposed within the gears so it is probably best not to spray lubrication into the unit after removing the main pin as the pot may become contaminated, apply lube to the pin directly.
• I rust cured and polished the main pin as it is exposed to the road spray at the bottom of the headlight bowl.
• The units are Wipac branded but I think that these are M.E.S. OEM. There are similar M.E.S. units available from vehicles from the mid/late-90s which could also make donor devices.
• The pin bellows does not grip the pin, which moves freely independent of the bellows, and likely to let water in. I am planning to put an O-ring on the pin behind the bellows when I find one suitable.

Hopefully it last another 23 years.